sealPurdue Science and Health Briefs

September 2000

Medications may increase sensitivity to sunlight

WEST LAFAYETTE, Ind. – Applying a sunscreen may help protect against the sun's burning rays, but if you're taking a medication, you may need to take additional precautions, says a Purdue University pharmacy expert.

Many widely used medications can cause an increased sensitivity to light in some individuals, resulting in hives, rashes, or other skin eruptions, says Gail Newton, associate professor of pharmacy practice.

These problems, called photosensitivity reactions, can occur when a person is exposed to sunlight and other types of ultraviolet light for even brief amounts of time, Newton says. Exposure to UV light in tanning beds and indirect sun exposure – such as light reflected off pavement – also can trigger these reactions.

Though dozens of medications may cause this problem, some of the more commonly used medications include some antihistamines, used in cold and allergy medicines; nonsteroidal anti-inflammatory drugs, used to control pain and inflammation; and antibiotics, including the tetracyclines and "sulfa" drugs, Newton says.

Other medications containing photoreactive agents include some antidepressants, antibiotics, anti-psychotics, cancer chemotherapy, cardiovascular drugs, diuretics and oral diabetes medications. The herbal remedy St. John's wort, sometimes used to treat depression, also has been associated with photosensitivity, she says.

"The exact reaction to sunlight exposure depends on the drug being used," she says. "With some medications, sunlight exposure can trigger a fine red rash, with others, patients burn more severely or more quickly than normal."

Though these drugs do not directly increase the risk of skin cancer, serious sunburns, particularly in children, have been associated with an increased incidence of skin cancers later in life, Newton says.

People using these types of medications should take extra precautions in the sun, Newton says.

"Ideally, people should avoid prolonged exposure to sunlight while using one of these medications," she says. "When exposure cannot be avoided, people should use a broad-spectrum sunscreen with an SPF of at least 15, preferably 30."

Newton recommends checking sunscreen labels for the ingredients zinc oxide, titanium oxide or avobenzone, which protect against both UVA and UVB rays.

"Though most sunburns are caused by UVB rays, some photosensitivity reactions are triggered by UVA rays," she says.

Newton says additional precautions include:

• Following the label directions. At least one full ounce – about three quarter-size dollops – of sunscreen should be applied 30 minutes prior to exposure. The product should be reapplied after swimming or excessive sweating.

• Wearing protective clothing. Wide-brimmed hats, sunglasses and tightly-woven, long-sleeved shirts and pants are recommended.

• Avoiding exposure during the high intensity hours of sunlight between 10 a.m. and 4 p.m.

Though medications associated with photosensitivity often come with warning labels, Newton says consumers may contact their pharmacist with questions on the risk of photosensitivity associated with any specific medication.

CONTACT: Gail Newton, (765) 494-1473,

Supercomputer gives Purdue research, teaching edge

WEST LAFAYETTE, Ind. – Purdue University has upgraded its research computing facilities with a $10 million IBM supercomputer, one of the most powerful research tools in the nation.

The RS/6000 SP supercomputer, which was installed this summer, is more than 15 times as powerful as the university's previous system, says John Steele, director of Purdue's Computing Center.

"The system is in the top 10 percent of the most powerful systems in North America, and certainly among the most powerful systems at any university in the Big Ten," Steele says.

The system contains 272 processors, working in parallel with a total memory of 288 gigabytes, or roughly 4,000 times more memory than the typical personal computers now on the market.

Engineers and scientists will use the system for research that requires such high-performance applications as complex simulations and calculations for modeling the structures of molecules and viruses, studying the human genome, global climate change and the effects of turbulence on aircraft, designing more effective drugs and work involving complex graphics. The system also will be used for research and studies in "parallel computing," a method that enables the smooth operation of many computers linked together.

Computation-based research is becoming more prevalent in many scientific and engineering disciplines, increasing the need for powerful computer systems, says Gary Isom, Purdue's vice president for research and dean of the graduate school.

The supercomputer was paid for, in part, with funding from the Indiana General Assembly earmarked specifically for high-technology upgrades. Because companies may have access to the computer system, it will help attract high-tech industries to the Purdue Research Park and to the state, Isom says. "It will certainly provide an economic benefit to the state of Indiana," he says.

The upgraded system will enable scientists to get far more reliable research results, says Carol Post, a professor of medicinal chemistry who specializes in biophysics and uses the current system to study viruses. "It will help tremendously," she says.

Steele says the system also will be compatible with other, even more powerful supercomputers, which will enable researchers at Purdue to collaborate with scientists worldwide via high-speed Internet connections.

CONTACT: John Steele, (765) 494-9646,

Compiled by Susan Gaidos, (765) 494-2081;

Purdue News Service: (765) 494-2096;

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